JP2001073123A - Ito target and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ITO target in which the generation of nodules in the process of sputtering can be evaded, the plane dispersion of the film forming rate is small, the change of the film forming rate is small from the initial stage to the last stage in the use, and the high film forming rate can be obtained and to provide a method for producing it. SOLUTION: In this producing method, raw material powder composed of indium oxide powder or indium oxide-tin oxide synthesized powder in which the average grain size is <=0.5 μm, and the ratio of the powder of 0.1 to 0.8 μm is >=85 wt.% of the whole and tin oxide powder in which the average grain size is <=2.5 μm, and the ratio of the powder of >=7.0 μm is <=10 wt.% is compacted at ordinary temperature under the pressure of >=1000 kg/cm2 to obtain a compacted body, the temperature of the compacted body is raised at 1000 to 1400 deg.C within 2 hours in an oxygen atmosphere under the ordinary pressure, in the process of the temperature rising, the dispersion of the temperature of the compacted body is controlled to the range of ±20 deg.C, and sintering is executed in such a manner that the dispersion of the temperature of the compacted body in the process of the retaining sintering is controlled to the range of ±10 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ITO target used as a raw material for forming a transparent conductive film by a sputtering method and a method for producing the same, and more particularly, to a high-density, low-nodule generation during sputtering and a stable film-forming rate. The present invention relates to an ITO target capable of performing sputtering with high power because of high thermal conductivity and a method of manufacturing the same.

[0002]

2. Description of the Related Art An ITO film is widely used as a transparent conductive film, and there is a sputtering method as a method for forming the ITO film. In the sputtering method, ITO
Use a target.

[0003] An ITO target is a raw material for forming an ITO film by a sputtering method. The raw material powder is made of indium oxide powder, tin oxide powder or, if necessary, indium oxide-tin oxide synthetic powder. It is manufactured by a powder sintering method of molding and baking.

[0004] Tin oxide has a higher vapor pressure than indium oxide and poor sinterability. On the other hand, tin oxide is inexpensive as a raw material at about 1/10 the price of indium oxide.
It is used to reduce the manufacturing cost of the O film. In order to lower the resistance value of the ITO film, an ITO target containing 5 to 10% by weight of tin oxide is usually used. However, in applications where the resistance value may be relatively high, the purpose is to reduce the target price. An ITO target containing a high concentration of tin oxide is used.

However, as the tin oxide concentration increases,
The density of the ITO target decreases. For this reason, nodules are generated on the surface of the ITO target during sputtering, resulting in a decrease in deposition rate, variation in deposition power, variation in deposition rate, generation of arc discharge, and the like.
In some cases, this may cause deterioration in film thickness distribution and film quality due to generation of particles.

For example, in the case of an ITO target manufactured by a conventional technique and containing 30% by weight of tin oxide, its density is at most 6.0 g / cm ^3. It is known that the film formation rate is 60% or less as compared with the initial stage of use, and that after use, 50% or more of the surface of the ITO target is covered with nodules.

Further, it is inevitable that pores exist on the surface and inside of the ITO target obtained by the powder sintering method. Furthermore, since tin oxide has a strong tendency to aggregate during mixing and sintering of powdery raw materials, large aggregates of tin oxide are likely to be generated in the obtained ITO target.

As a result, the thermal conductivity of the ITO target decreases, and the heat applied to the surface of the ITO target during sputtering cannot be sufficiently dissipated.
Cracks and peeling of the target and occurrence of abnormal discharge occur, causing abnormalities in sputtering and film quality.

For example, cold press (cold press molding)
Thereafter, the thermal conductivity of the ITO target produced by pressure sintering in oxygen is approximately 5 to 7 W / mK. In this case, since the heat dissipation is poor, the power applied during sputtering is increased to at most 20 W / mK. It could only be raised to about cm ² . With such a low power, a sufficient film formation rate could not be obtained, leading to a decrease in productivity.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, improves the density of an ITO target containing a high concentration of tin oxide, avoids the generation of nodules during sputtering, and reduces the deposition rate. In-plane variation is small, the change in deposition rate is small from the beginning of use to the end of use, and
An object of the present invention is to provide an ITO target capable of increasing a sputtering power because of its high thermal conductivity and consequently obtaining a high film forming rate, and a method of manufacturing the same.

[0011]

The ITO target of the present invention is an indium tin oxide having a composition of 20% by weight or less of tin oxide, an average density of 7.0 g / cm ³ or more, and a variation in density of average. The density is within a range of ± 0.05 g / cm ³ , and the thermal conductivity is 8.0 W / mK or more.

Alternatively, the composition exceeds 20% by weight of tin oxide,
And a indium tin oxide 35 wt% or less, and the average density of 6.8 g / cm ³ or more, in the range of ± 0.05 g / cm ³ variations in density to the average density,
Thermal conductivity is 8.0 W / mK or more.

[0013] Alternatively, indium tin oxide having a composition exceeding 35% by weight of tin oxide, and having an average density of 6.5 g / cm3.
³ or more, and the variation in density is ± 0.
05 g / cm ³ and a thermal conductivity of 8.0 W /
mK or more.

The variation in the density is ±± with respect to the average density.
Desirably, it is in the range of 0.03 g / cm ³ .

In the method of the present invention for producing such an ITO target, the average particle diameter is 0.5 μm or less, preferably 0.4 μm or less, and the particle diameter is 0.1 μm or more and 0.8 μm or less.
85% by weight or more, preferably 90% by weight
The above, more preferably 95% by weight or more of indium oxide powder and / or indium oxide tin oxide synthetic powder, and an average particle size of 2.5 μm or less, preferably 2.0 μm or less.
Raw material powder in which powder having a particle size of 7.0 μm or less and tin oxide powder occupying 10% by weight or less, preferably 5% by weight or less, and more preferably 3% by weight or less is mixed at a desired ratio, and 1000 kg / Cm ² to obtain a molded body under pressure at a pressure of not less than
The temperature is raised from 1000 ° C to 1400 ° C within 2 hours,
During the heating, the temperature variation of the compact is within ± 20 ° C., the sintering holding temperature is 1400 ° C. to 1450 ° C., and the temperature variation of the compact during sintering is ± 10 ° C. Sinter.

The raw material powder before pressure molding is prepared by adding an average particle size of 1
It is desirable to size the granules to a size of 0 μm or more. For this purpose, it is preferable to add and mix a molding binder such as PVA or to temporarily sinter the raw material powder in air at 300 to 600 ° C.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ITO target of the present invention has a density of 7.0 g / c when the composition is 20% by weight or less of tin oxide.
m ³ or more, the density is 6.8 g / cm ³ or more when the composition is 20 to 35% by weight of tin oxide, or 6.5 g / cm ³ or more when the composition exceeds 35% by weight of tin oxide. If the densities do not reach the respective densities according to the composition ratio of tin oxide, nodules are generated during sputtering, and the deposition rate decreases, the deposition power and the deposition rate vary, and arc discharge occurs. Further, the film thickness distribution is deteriorated and the film quality is deteriorated.

The thermal conductivity of the ITO target of the present invention is:
8.0 W / mK or more. Thermal conductivity 8.0W / mK
If it is less than 1, the heat dissipation of the ITO target during sputtering becomes insufficient, and the ITO target cracks or peels off.
Abnormal discharge occurs, which causes abnormalities in sputtering and film quality. In order to avoid these, the sputtering power must be reduced, and the productivity is reduced.

The variation in the density of the ITO target of the present invention is within a range of ± 0.05 g / cm ³ of the average density. By setting it within this range, the film forming speed is constant within the target surface, and does not change from the initial use to the end of use.

The raw material powder of the ITO target of the present invention comprises:
Particles having an average particle diameter of 0.5 μm or less, preferably 0.4 μm or less, and a particle diameter of 0.1 μm or more and 0.8 μm or less account for 85% by weight or more, preferably 90% by weight or more, and more preferably 95% by weight or more. Occupied indium oxide powder or indium oxide tin oxide synthetic powder and average particle size of 2.5 μm
Or less, preferably 2.0 μm or less, powder having a particle size of 7.0 μm or more is 10% by weight or less, preferably 5% by weight or less,
More preferably, tin oxide powder occupying 3% by weight or less is mixed at a desired ratio. If you deviate from these ranges,
Desired sintering density and thermal conductivity cannot be obtained.

It is desirable that the raw material powder is sized to have a mean particle size of 10 μm or more.

By this, at the time of pressure molding described later,
Fluidity when filling the raw material powder into the mold is improved. In order to size the granules, for example, a binder for molding such as PVA is added and mixed, or
What is necessary is just to perform temporary sintering at 600 degreeC.

The raw material powder is 1000 kg at room temperature.
/ Cm ² to obtain a molded body. At a pressure lower than this, it becomes difficult to obtain the desired sintering density and thermal conductivity. In addition, when the raw material powder is sized into granules, a pressure higher than that required to completely break the granules is required.

The above-mentioned molded body is placed in an oxygen atmosphere at normal pressure,
The temperature is raised from 000 ° C. to 1400 ° C. within 2 hours, the temperature variation is within ± 20 ° C. during the temperature increase, the sintering holding temperature is 1400 ° C. to 1450 ° C., and the green compact during sintering holding Is within the range of ± 10 ° C.

The oxygen atmosphere refers to a pure oxygen atmosphere or a high-concentration oxygen atmosphere. The pressure in the sintering atmosphere is sufficient at normal pressure. Under such sintering conditions, an ITO target having high uniform density and high thermal conductivity can be obtained.

Hereinafter, embodiments of the present invention will be described.

(Example 1) The average particle size of the raw material powder was 0.35 μm, and as a particle size distribution, 0.2% of powder having a particle size of 0.1 μm or less, 4.2% of powder having a particle size of 0.8 μm or more, That is, 95.6% of powder having a size of 0.1 μm or more and 0.8 μm or less.
90% by weight of indium oxide powder having an average particle size of 1.8
powder having a particle size distribution of 7.0 μm or more is 2.2.
% Tin oxide powder and 10% by weight, and 1% by weight of PVA was added as a molding binder, and then sized at 30 to 50 μm using granules at room temperature at 2000 kg / cm ^2. 400m at a pressure of
A molded product of mx 500 mm x 10 mm was obtained.

The obtained molded body is subjected to 100 atmospheric pressure oxygen.
The temperature range from 0 ° C. to 1400 ° C. was raised in 2 hours, and the temperature was kept at 1400 ° C. for 10 hours to perform sintering. The temperature distribution of the compact at the time of temperature rise is within ± 18 ° C,
During the holding at 400 ° C., the temperature distribution of the molded body is within the range of ± 4 ° C. Of the two ITO targets created, 1
One was subjected to measurement of thermal conductivity and density distribution, and one was subjected to sputtering.

As a result, the thermal conductivity was 9.5 W / mK. The density of the entire ITO target is 7.07 g / cm.
³ , the density in an arbitrary 1 cm square area has a minimum value of 7.02 g / cm ³ and a maximum value of 7.12 g / cm ^3.
Met. The density variation in the thickness direction is minimum 7.03 g / cm ^3, the maximum value was 7.11 g / cm ^3.

In the sputtering, after bonding the ITO target to the backing plate, DC sputtering was performed, and the maximum power that could be sputtered was examined while gradually increasing the power. As a result, even when a power of 30 W / cm ² was applied, no abnormality such as a crack was found on the surface of the ITO target. The film formation rate was about 1.5 times as high as that of the conventional ITO target.

When the film formation rate and the film thickness distribution of the obtained ITO film were measured at the beginning and end of use, the film formation rate was 94% at the end of use relative to the beginning of use. Also,
The film thickness distribution in the substrate plane was within the range of ± 5%. After use, the surface of the ITO target was observed, and no nodules were formed.

(Example 2) The average particle size of the raw material powder was 0.38 μm, and as a particle size distribution, 2.2% of powder having a particle size of 0.1 μm or less, 6.8% of powder having a particle size of 0.8 μm or more, That is, 91.0% of powder of 0.1 μm or more and 0.8 μm or less
90% by weight of indium oxide powder having an average particle size of 2.1
powder having a particle size distribution of 7.0 μm or more is 4.2 μm.
% Tin oxide powder and 10% by weight, and 1% by weight of PVA was added as a molding binder, and then sized at 30 to 50 μm using granules at room temperature at 2000 kg / cm ^2. 400m at a pressure of
A molded product of mx 500 mm x 10 mm was obtained.

The obtained molded product is subjected to 100 atmospheric pressure oxygen.
The temperature was raised from 0 ° C. to 1450 ° C. in 1.5 hours, kept at 1450 ° C. for 15 hours, and sintered. The temperature distribution of the compact at the time of temperature rise is within ± 18 ° C,
During the holding at 450 ° C., the temperature distribution of the molded body is within the range of ± 4 ° C. Of the two ITO targets created, 1
One was subjected to measurement of thermal conductivity and density distribution, and one was subjected to sputtering.

As a result, the thermal conductivity was 10.2 W / mK. The density of the entire ITO target is 7.13 g / c
m ³ , and the density in an arbitrary 1 cm square area has a minimum value of 7.08 g / cm ³ and a maximum value of 7.18 g / cm 3
^{Was 3} . The minimum value of the density variation in the thickness direction was 7.09 g / cm ³ , and the maximum value was 7.17 g / cm ³ .

In the sputtering, after bonding the ITO target to the backing plate, DC sputtering was performed, and the maximum power that could be sputtered was examined while gradually increasing the power. As a result, even when a power of 30 W / cm ² was applied, no abnormality such as a crack was found on the surface of the ITO target. The film formation rate was about 1.5 times as high as that of the conventional ITO target.

When the film formation rate and the film thickness distribution of the obtained ITO film were measured at the beginning and end of use, the film formation rate was 92% of that at the end of use. Also,
The film thickness distribution in the substrate plane was within the range of ± 5%. After use, the surface of the ITO target was observed, and no nodules were formed.

(Example 3) The average particle size of the raw material powder was 0.33 µm, and as a particle size distribution, 3.6% of powder having a size of 0.1 µm or less, 6.3% of powder having a size of 0.8 µm or more, That is, 90.1% of powder of 0.1 μm or more and 0.8 μm or less
90% by weight of indium oxide powder having an average particle size of 1.9
powder having a particle size distribution of 7.0 μm or more is 2.2.
% Tin oxide powder and 10% by weight, and 1% by weight of PVA was added as a molding binder, and then sized at 30 to 50 μm using granules at room temperature at 2000 kg / cm ^2. 400m at a pressure of
A molded product of mx 500 mm x 10 mm was obtained.

[0038] The obtained molded body is immersed in oxygen at normal pressure for 100 hours.
The temperature range from 0 ° C. to 1400 ° C. was raised in 2 hours, and the temperature was kept at 1400 ° C. for 10 hours to perform sintering. The temperature distribution of the compact at the time of temperature rise is within ± 18 ° C,
During the holding at 400 ° C., the temperature distribution of the molded body is within the range of ± 4 ° C. Of the two ITO targets created, 1
One was subjected to measurement of thermal conductivity and density distribution, and one was subjected to sputtering.

As a result, the thermal conductivity was 8.5 W / mK. The overall density of the ITO target is 6.95 g / cm
³ , the density in an arbitrary 1 cm square area has a minimum value of 6.91 g / cm ³ and a maximum value of 7.00 g / cm ^3.
Met. The density variation in the thickness direction is minimum 6.95 g / cm ^3, the maximum value was 6.99 g / cm ^3.

In the sputtering, after bonding the ITO target to the backing plate, DC sputtering was performed, and the maximum power that could be sputtered was examined while gradually increasing the power. As a result, even when a power of 25 W / cm ² was applied, no abnormality such as a crack was found on the surface of the ITO target. The film formation rate was about 1.2 times higher than the conventional ITO target.

When the film formation rate and the film thickness distribution of the obtained ITO film were measured at the beginning and end of use, the film formation rate was 90% of that at the end of use. Also,
The film thickness distribution in the substrate plane was within the range of ± 5%. When the ITO target surface was observed after use, nodule generation was observed in a small area, and the area was only 6.3% of the entire area.

The thermal conductivity of the conventional ITO target was about 5 to 7 W / mK, and the power applied during sputtering could only be increased to about 20 W / cm ² at most. The thermal conductivity of the ITO target of No. 1 to No. 3 is 8.5 to 10.2 W / mK, and the power applied during sputtering is 25 to 30 W / mK.
W / cm ² could be increased.

Accordingly, the film forming speed is set to be approximately 1.2 to 1.
The speed can be increased five times, and the productivity can be remarkably improved.

Example 4 The particle size of the raw material powder was 0.35 μm in average particle size, and as a particle size distribution, 0.2% was powder having a particle size of 0.1 μm or less, 4.2% was powder having a particle size of 0.8 μm or more. That is, 95.6% of powder having a size of 0.1 μm or more and 0.8 μm or less.
90% by weight of indium oxide powder having an average particle size of 2.2
After mixing 10% by weight of tin oxide powder of 10 μm and adding 1% by weight of PVA as a binder for molding, 30 μm
Using granules sized from 50 to 50 μm in size,
At room temperature, at a pressure of 2000 kg / cm ² , 400
A molded product of mm × 500 mm × 10 mm was obtained.

The obtained molded product was subjected to 150 atmospheric pressure oxygen.
The temperature was kept at 0 ° C. for 10 hours to perform sintering. The temperature distribution of the molded body at the time of temperature rise is within the range of ± 18 ° C, and the temperature distribution of the molded body is within the range of ± 4 ° C during holding at 1500 ° C. 2
One of the prepared ITO targets was subjected to measurement of thermal conductivity and density distribution, and one was subjected to sputtering.

As a result, the thermal conductivity was 9.1 W / mK. The overall density of the ITO target is 7.10 g / cm
³ , the density in an arbitrary 1 cm square area has a minimum value of 7.09 g / cm ³ and a maximum value of 7.12 g / cm ^3.
Met. The minimum value of the density variation in the thickness direction was 7.09 g / cm ³ , and the maximum value was 7.11 g / cm ³ .

In the sputtering, after the ITO target was bonded to the backing plate, DC sputtering was performed, and the film formation speed and film thickness distribution of the obtained ITO film were measured at the initial stage and at the end of use. On the other hand, it was 97% at the end of use. Further, the film thickness distribution in the substrate surface was within a range of ± 5%. After use, the surface of the ITO target was observed, and no production of nodules was observed.

(Example 5) The average particle size of the raw material powder was 0.42 μm, and as a particle size distribution, 2.8% of powder having a particle size of 0.1 μm or less, 6.3% of powder having a particle size of 0.8 μm or more, That is, 90.9% of powder of 0.1 μm or more and 0.8 μm or less is used.
90% by weight of indium oxide powder having an average particle size of 2.3
After mixing 10% by weight of tin oxide powder of 10 μm and adding 1% by weight of PVA as a binder for molding, 30 μm
Using granules sized from 50 to 50 μm in size,
At room temperature, at a pressure of 2000 kg / cm ² , 400
A molded product of mm × 500 mm × 10 mm was obtained.

The obtained molded product was subjected to 150 atmospheric pressure oxygen.
The temperature was kept at 0 ° C. for 10 hours to perform sintering. The temperature distribution of the molded body at the time of temperature rise is within the range of ± 18 ° C, and the temperature distribution of the molded body is within the range of ± 4 ° C during holding at 1500 ° C. 2
One of the prepared ITO targets was subjected to measurement of thermal conductivity and density distribution, and one was subjected to sputtering.

As a result, the thermal conductivity was 8.8 W / mK. The density of the entire ITO target is 7.07 g / cm.
Is ^3, the minimum value is 7.05 g / cm ³ density at any 1cm square area, maximum 7.10 g / cm ³
Met. The minimum value of the density variation in the thickness direction was 7.06 g / cm ³ , and the maximum value was 7.09 g / cm ³ .

In the sputtering, after the ITO target was bonded to the backing plate, DC sputtering was performed, and the film formation speed and film thickness distribution of the obtained ITO film were measured at the initial stage and at the end of use. On the other hand, it was 94% at the end of use. Further, the film thickness distribution in the substrate plane was within the range of ± 6%. When the ITO target surface was observed after use, nodule formation was found in only a small part, and the area was only 0.4% of the entire area.

(Example 6) The average particle size of the raw material powder was 0.30 μm, and as a particle size distribution, 4.2% of powder having a particle size of 0.1 μm or less, 10.2% of powder having a particle size of 0.8 μm or more, That is, powder having a particle size of 0.1 μm or more and 0.8 μm or less is 85.6.
% Indium oxide powder of 90% by weight and an average particle size of 4.
5 μm of tin oxide powder was mixed with 10% by weight, and 1% by weight of PVA was added as a molding binder.
Using granules sized to particles having a size of m to 50 μm, at normal temperature, at a pressure of 2000 kg / cm ² ,
A molded product of 00 mm × 500 mm × 10 mm was obtained.

[0053] The obtained molded product is subjected to 150
The temperature was kept at 0 ° C. for 10 hours to perform sintering. The temperature distribution of the molded body at the time of temperature rise is within the range of ± 18 ° C, and the temperature distribution of the molded body is within the range of ± 4 ° C during holding at 1500 ° C. 2
One of the prepared ITO targets was subjected to measurement of thermal conductivity and density distribution, and one was subjected to sputtering.

As a result, the thermal conductivity was 8.6 W / mK. The overall density of the ITO target is 7.10 g / cm
³ , the density in an arbitrary 1 cm square area has a minimum value of 7.02 g / cm ³ and a maximum value of 7.12 g / cm ^3.
Met. The minimum value of the density variation in the thickness direction was 7.00 g / cm ³ , and the maximum value was 7.13 g / cm ³ .

In the sputtering, after the ITO target was bonded to the backing plate, DC sputtering was performed, and the film formation rate and film thickness distribution of the obtained ITO film were measured at the beginning and end of use. On the other hand, it was 82% at the end of use. Further, the film thickness distribution in the substrate plane was within a range of ± 9%. When the ITO target surface was observed after use, nodule formation was observed only in an area of about 8.6% of the target surface.

The density manufactured by the conventional technique is 7.0.
The deposition rate of the ITO film obtained by sputtering with an ITO target of 0 g / cm ³ is 70% or less at the end of use compared to the initial use, and the film thickness distribution on the substrate surface is ± 9 to 12%. Was within the range. In addition, I
On the TO target surface, nodule generation was observed in a region of 50% or more.

On the other hand, the ITO taps of Embodiments 4 to 6
The target density is 7.0 g / cm ^ThreeThat's all for the spa
The deposition rate of the ITO film obtained by
At the end of use, it was 82% or more. In addition,
The film thickness distribution in the plate surface was in the range of ± 5 to 9%. Further
About 8.6% or less of the surface of the used ITO target
Nodule formation was observed only in the region.

In particular, the density in an arbitrary 1 cm square area is within a range of ± 0.03 g / cm ³ with respect to the entire average density, and the density in an arbitrary 1 mm thick area is the entire average density. On the other hand, the deposition rate of the ITO film obtained by sputtering with the ITO targets of Examples 4 and 5 in the range of ± 0.03 g / cm ³ was 94% or more at the end of use with respect to the initial use. In this case, the film thickness distribution in the substrate surface was in the range of ± 5 to 6%.

Further, on the surface of the used ITO target, nodule formation was observed only in a region of about 0.40% or less, indicating that the ITO target of the present invention was excellent.

(Example 7) The average particle size of the raw material powder was 0.35 μm, and as a particle size distribution, 0.2% of powder having a particle size of 0.1 μm or less, 4.2% of powder having a particle size of 0.8 μm or more, That is, 95.6% of powder having a size of 0.1 μm or more and 0.8 μm or less.
70% by weight of indium oxide powder having an average particle size of 1.8
powder having a particle size distribution of 7.0 μm or more is 2.2.
% Tin oxide powder and 30% by weight, and 1% by weight of PVA was added as a binder for molding, and then sized at 30 to 50 μm using granules at room temperature at 2000 kg / cm ^2. 400m at a pressure of
A molded product of mx 500 mm x 10 mm was obtained.

[0061] The obtained molded product is subjected to 150
The temperature was kept at 0 ° C. for 10 hours to perform sintering. The temperature distribution of the molded body at the time of temperature rise is within the range of ± 18 ° C, and the temperature distribution of the molded body is within the range of ± 4 ° C during holding at 1500 ° C. 2
One of the prepared ITO targets was subjected to measurement of thermal conductivity and density distribution, and one was subjected to sputtering.

As a result, the thermal conductivity was 9.3 W / mK. The overall density of the ITO target is 6.90 g / cm
Is ^3, the minimum value is 6.88 g / cm ³ density at any 1cm square area, maximum 6.95 g / cm ³
Met. The density variation in the thickness direction was a minimum value of 6.86 g / cm ³ and a maximum value of 6.94 g / cm ³ .

In the sputtering, after the ITO target was bonded to the backing plate, DC sputtering was performed, and the film formation rate and film thickness distribution of the obtained ITO film were measured at the beginning and end of use. On the other hand, it was 88% at the end of use. Further, the film thickness distribution in the substrate surface was within a range of ± 5%. When the ITO target surface was observed after use, nodule formation was observed in a very small area, and its area was only 2.5% of the entire area.

(Example 8) The average particle size of the raw material powder was 0.38 µm, and as a particle size distribution, 2.2% of powder having a particle size of 0.1 µm or less, 6.8% of powder having a particle size of 0.8 µm or more, That is, 91.0% of powder of 0.1 μm or more and 0.8 μm or less
60% by weight of indium oxide powder having an average particle size of 2.1
powder having a particle size distribution of 7.0 μm or more is 4.2 μm.
% Tin oxide powder and 40% by weight, and 1% by weight of PVA was added as a molding binder, and then sized at 30 to 50 μm using granules at room temperature at 2000 kg / cm ^2. 400m at a pressure of
A molded product of mx 500 mm x 10 mm was obtained.

[0065] The obtained molded product is subjected to 150
The temperature was kept at 0 ° C. for 10 hours to perform sintering. The temperature distribution of the molded body at the time of temperature rise is within the range of ± 18 ° C, and the temperature distribution of the molded body is within the range of ± 4 ° C during holding at 1500 ° C. 2
One of the prepared ITO targets was subjected to measurement of thermal conductivity and density distribution, and one was subjected to sputtering.

As a result, the thermal conductivity was 8.9 W / mK. The overall density of the ITO target is 6.52 g / cm.
Is ^3, the minimum value is 6.50 g / cm ³ density at any 1cm square area, maximum 6.56 g / cm ³
Met. The density variation in the thickness direction was a minimum value of 6.48 g / cm ³ and a maximum value of 6.55 g / cm ³ .

In the sputtering, after the ITO target was bonded to the backing plate, DC sputtering was performed, and the film formation rate and film thickness distribution of the obtained ITO film were measured at the beginning and end of use. On the other hand, it was 75% at the end of use. Further, the film thickness distribution in the substrate surface was within a range of ± 5%. When the ITO target surface was observed after use, nodule formation was observed in a small area, and its area was only 12.4% of the entire area.

(Example 9) The average particle size of the raw material powder was 0.33 µm, and as a particle size distribution, 3.6% of powder having a size of 0.1 µm or less, 6.3% of powder having a size of 0.8 µm or more, That is, 90.1% of powder of 0.1 μm or more and 0.8 μm or less
55% by weight of indium oxide powder having an average particle size of 1.9
powder having a particle size distribution of 7.0 μm or more is 2.2.
% Tin oxide powder and 45% by weight of tin oxide powder, 1% by weight of PVA was added as a molding binder, and sized at 30 to 50 μm using granules at room temperature at 2000 kg / cm ^2. 400m at a pressure of
A molded product of mx 500 mm x 10 mm was obtained.

The obtained molded product was subjected to 150
The temperature was kept at 0 ° C. for 10 hours to perform sintering. The temperature distribution of the molded body at the time of temperature rise is within the range of ± 18 ° C, and the temperature distribution of the molded body is within the range of ± 4 ° C during holding at 1500 ° C. 2
One of the prepared ITO targets was subjected to measurement of thermal conductivity and density distribution, and one was subjected to sputtering.

As a result, the thermal conductivity was 8.8 W / mK. The overall density of the ITO target is 6.68 g / cm.
Is ^3, the minimum value is 6.65 g / cm ³ density at any 1cm square area, maximum 6.71 g / cm ³
Met. The density variation in the thickness direction is minimum 6.66 g / cm ^3, the maximum value was 6.72 g / cm ^3.

In the sputtering, after the ITO target was bonded to the backing plate, DC sputtering was performed, and the film formation rate and film thickness distribution of the obtained ITO film were measured at the beginning and end of use. On the other hand, it was 81% at the end of use. Further, the film thickness distribution in the substrate surface was within a range of ± 5%. When the ITO target surface was observed after use, nodule formation was observed in a very small area, and its area was only 9.4% of the entire area.

Conventional ITO containing 30% by weight of tin oxide
The density of the target was at most 6.0 g / cm ³ , and the deposition rate of the ITO film obtained by sputtering was 60% or less at the end of use compared to the initial use. Also,
The film thickness distribution in the substrate plane was in the range of ± 8 to 12%.
Further, on the target surface after use, generation of nodules was observed in a region of 50% or more.

On the other hand, the ITO tars of Examples 7 to 9
The get density is 6.52 g / cm ^ThreeThat's all for the spa
The deposition rate of the ITO film obtained by
It was 75% or more at the end of use. In addition,
The film thickness distribution in the plate surface was within the range of ± 5%. further,
Nodule raw material is placed on the surface of the used ITO target.
Formation was observed only in the region of about 12.40% or less.

In particular, the density in an arbitrary 1 cm square area is within a range of ± 0.05 g / cm ³ with respect to the entire average density, and the density in an arbitrary 1 mm thickness area is the entire average density. On the other hand, since it is within the range of ± 0.05 g / cm ³ , the deposition rate of the ITO film obtained by sputtering is high as described above, I have.

The film thickness distribution on the substrate surface was within the range of ± 5%. Furthermore, the generation of nodules on the surface of the ITO target after use is low. In the present invention, it was possible to provide an ITO target suitable for sputtering even if the cost was kept low by increasing the proportion of tin oxide.

(Comparative Example 1) The average particle size of the raw material powder was 0.6 μm, and as a particle size distribution, 0.2% of powder having a particle size of 0.1 μm or less, 16.8% of powder having a particle size of 0.8 μm or more, That is, powder of 0.1 μm or more and 0.8 μm or less has 90% by weight of 83% indium oxide powder, and the average particle diameter is 2.6 μm.
m, as a particle size distribution, a powder having a particle size of 7.0 μm or more was mixed with 10% by weight of 11% tin oxide powder, and a molded product was obtained in the same manner as in Example 1; Sintered.

As a result, the thermal conductivity was 7.2 W / mK, I
The density of the entire TO target was 6.98 g / cm ³ , and the density in an arbitrary 1 cm square area was a minimum value of 6.92 g / cm ³ and a maximum value of 7.04 g / cm ³ . The minimum value of the density variation in the thickness direction is 6.9.
6g / cm ^3, the maximum value was 7.04g / cm ^3.

In the sputtering, after bonding the ITO target to the backing plate, DC sputtering was performed, and the maximum power that could be sputtered was examined while gradually increasing the power. As a result, cracks occurred on the surface of the ITO target when a power of 20 W / cm ² was applied.

When the film formation rate and the film thickness distribution of the obtained ITO film were measured at the beginning and end of use, the film formation rate was 66% at the end of use relative to the beginning of use. Also,
The film thickness distribution in the substrate plane was within the range of ± 10%. After use, when the surface of the ITO target was observed, nodules were formed in 50% or more of the entire area.

(Comparative Example 2) Molding pressure is 900 kg / cm
Except for ² , when an ITO target was prepared in the same manner as in Example 1, the thermal conductivity was 6.7 W / mK. The density of the entire ITO target is 6.98 g / cm ^3.
The minimum density of an arbitrary 1 cm square area was 6.92 g / cm ³ , and the maximum density was 7.05 g / cm ³ . The minimum value of the density variation in the thickness direction is 6.
93 g / cm ³ , and the maximum value was 7.03 g / cm ³ .

In the sputtering, after the ITO target was bonded to the backing plate, DC sputtering was performed, and the film formation rate and film thickness distribution of the obtained ITO film were measured at the beginning and end of use. On the other hand, it was 67% at the end of use. The film thickness distribution in the substrate plane was within ± 10%. After use, when the surface of the ITO target was observed, nodules were formed in 35% or more of the entire area.

(Comparative Example 3) A molded product similar to that of Example 1 was used.
The temperature range from 1000 to 1400 ° C. in oxygen is 2.5
Then, the temperature was slowly increased, and the temperature was maintained at 1400 ° C. for 10 hours to perform sintering. The temperature distribution of the molded body at the time of temperature rise is within the range of ± 18 ° C, and the temperature distribution of the molded body is within the range of ± 4 ° C during holding at 1400 ° C. Two IT created
One of the O targets was subjected to measurement of thermal conductivity and density distribution, and one was subjected to sputtering.

As a result, the thermal conductivity was 6.5 W / mK. The density of the entire ITO target is 6.99 g / cm.
Is ^3, the minimum value is 6.94 g / cm ³ density at any 1cm square area, maximum 7.04 g / cm ³
Met. The density variation in the thickness direction was a minimum value of 6.93 g / cm ³ and a maximum value of 7.04 g / cm ³ .

In the sputtering, after the ITO target was bonded to the backing plate, DC sputtering was performed, and the film formation rate and film thickness distribution of the obtained ITO film were measured at the beginning and end of use. On the other hand, it was 62% at the end of use. Further, the film thickness distribution in the substrate plane was within a range of ± 15%. After use, when the surface of the ITO target was observed, nodules were formed in 50% or more of the entire area.

(Comparative Example 4) A molded product similar to that of Example 1 was used.
The temperature was raised from 1000 to 1400 ° C. in oxygen in 2 hours, and the temperature was kept at 1400 ° C. for 10 hours to perform sintering.

The temperature distribution of the molded body at the time of raising the temperature
Beyond the range of 20 ° C. and within the range of ± 21 ° C., 14
During the holding at 00 ° C., the temperature distribution of the molded product is within ± 1 of the present invention.
Beyond the 0 ° C range, it was within ± 11 ° C. One of the two ITO targets was subjected to measurement of thermal conductivity and density distribution, and one was subjected to sputtering.

As a result, the thermal conductivity was 6.0 W / mK. The density of the entire ITO target is 6.93 g / cm.
Is ^3, the minimum value is 6.88 g / cm ³ density at any 1cm square area, maximum 6.99 g / cm ³
Met. The density variation in the thickness direction was a minimum value of 6.88 g / cm ³ and a maximum value of 6.98 g / cm ³ .

In the sputtering, after the ITO target was bonded to the backing plate, DC sputtering was performed, and the film formation rate and film thickness distribution of the obtained ITO film were measured at the beginning and end of use. On the other hand, it was 55% at the end of use. Further, the film thickness distribution in the substrate plane was within a range of ± 14%. When the ITO target surface was observed after use, nodules were formed in 80% or more of the entire area.

[0089]

According to the present invention, a high-density target can be obtained in an ITO target containing a high concentration of tin oxide. As a result, the generation of nodules during sputtering is suppressed to a small extent, and the in-plane variation in the deposition rate is reduced. An ITO target that is small or has a small change in the deposition rate from the early stage to the final stage of use of the target is provided.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Itaru Nanjo 2-8-1 Suehirocho, Ome-shi, Tokyo Sumitomo Metal Mining Co., Ltd. Electronics Business Unit F-term (reference) 4G030 AA34 AA39 BA02 BA15 BA21 GA01 GA05 GA25 GA28 4K029 BA50 BC09 CA05 DC05 DC09

Claims (6)

[Claims] 1. An indium tin oxide having a composition of 20% by weight or less of tin oxide, an average density of 7.0 g / cm ³ or more, and a variation in density of ± 0.05 g / cm ³ with respect to the average density.
An ITO target having a thermal conductivity of 8.0 W / mK or more in a range of cm ³ . 2. A composition comprising more than 20% by weight of tin oxide and 3% by weight.
5 percent by weight or less of indium tin oxide, the average density is not less 6.8 g / cm ³ or more, in the range variation with respect to the average density of ± 0.05 g / cm ³ of density, thermal conductivity An ITO target having a power of 8.0 W / mK or more. 3. An indium tin oxide having a composition exceeding 35% by weight of tin oxide, an average density of 6.5 g / cm ³ or more, and a variation in density of ± 0.05 g with respect to the average density.
/ Cm ³ , and a thermal conductivity of 8.0 W / mK or more. 4. An average particle size of 0.5 μm or less and a particle size of 0.5 μm.
One or more powders selected from the group consisting of indium oxide powder and indium oxide-tin oxide synthetic powder in which particles having a particle size of 1 μm to 0.8 μm account for 85% by weight or more; 1 μm or more powder
A raw material powder obtained by mixing tin oxide powder occupying 0% by weight or less at a desired ratio is molded under pressure at a pressure of 1000 kg / cm ² or more to obtain a molded product. Then, the temperature is raised from 1000 ° C. to 1400 ° C. within 2 hours. During the temperature rise, the temperature variation of the compact is within ± 20 ° C., the sintering holding temperature is 1400 ° C. to 1450 ° C., and the sintering holding is performed. A method for manufacturing an ITO target, wherein sintering is performed with a temperature variation of a green body in a range of ± 10 ° C. 5. The IT according to claim 4, wherein the raw material powder before pressure molding is sized into granules having an average particle size of 10 μm or more.
Manufacturing method of O target. 6. The one or more powders having an average particle size of 0.4 μm.
6. The method for manufacturing an ITO target according to claim 4, wherein m is equal to or less than m.